This story is from a high level mini campaign that I am currently running. I have a party of 5 people on a quest to free some gods from being trapped in the mortal realm by 4 lords who stole their power. The party consisted of a Pact of Undying Warlock, a Warforged Barbarian, a Kalashtar sorcerer/paladin, a Kalashtar barbarian, and a kitsune druid. On this particular session they had to find the Lord of Fire and Chaos in our sorc/pal's home town. The town had been overrun by a cult that was celebrating their goddess by drinking water that was holding a plague that turned people into random monsters. Most of the time it was a zombie or a ghoul, but sometimes stronger people turned into stronger monsters.
This is what the cult wanted and did it like a circus, making big elaborate performances to transform with. When the party first came to the town, they were greeted by a camp of paladins that had scouted out the place but were being held back by the barricades and the spell casters. The Warforged Barbarian decided he didn't care and tried to charge in, only to be met with a huge fireball as he stepped on a trap. So instead they had to find another way in. They had 2 choices. Either they could take the main market road but be exposed to a lot of cultists they could fight through, or they could sneak by the coastline where there isn't any cultists. Only one giant lava creature the size of Godzilla patrolling the coast. The party, being high level, thought at first this creature must be the chaos lord and this is the way they need to go to kill it. But first they decided to go and kill some cultists on the main road first.
As they reached the main road, they saw a makeshift stage with a woman tied up and 2 cultists giving off a big performance before taking a jug of the corrupted water and raising it to pour all over the woman. Our party blocked them by having the sorc/pal cast Wall of Fire around the woman. The cultists gave a sharp whistle and the party was surrounded. A long and bloody battle later, the party rescues the woman. The woman, named Kilana, was captured while looking for her little brother Jared. He was last seen near the coast, where the giant lava monster was. The party told her and she panicked, running off to save her brother.
The party had to act fast if he wanted to save them so they ran to the coast. As they got there, they saw a zombie cultist wandering around the abandoned coast, only to be smashed and burned by the giant lava monster. The monster was speaking Abyssal, which none of the party could understand. So as they readied their attack, Kilana ran around the corner, looked up and caught the eye of the monster. The monster growled at first then stopped and said "S…..sister?"
"Oh Jared," said Kilana, "what have they done to you?" This reveal stopped the party in their tracks. This giant monster is her little brother? The sorc/pal then cast telepathy and spoke with Jared. It turned out the cultists forced him to drink the water which turned him into the giant lava monster. He had almost forgotten who he was until his big sister came into view. It was clear at this point that he was not the lord that had taken the God's powers, but he knew who did. He decided to help the party find the real lord, who was being worshipped by this cult, and help put an end to this.